Combined telephone and alarm or kindred service system.



w. w. ISBAN.

COMBINED TELEPHONE AND ALARM 0E KINDBED SERVIGE SYSTEM.

LPPLIOATIOK FILED APLSO, 1903.

Patented Aug. 9, 1910.

` SIHEETS-SBEET 1.

W. W. DEAN.

OOHBIXBD TELEPHONE AND ALARM 0B KINDBBD SERVICE SYSTEM.

PPLIOATIOI FILED AIB.30, 1903.

Patented Aug. 9, 191i).

'Z SHEETS-SHEET 2.

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l Y .UNITED STATES PATENT ernten.

WILLIAM W. DEAN, OF CHICAGO. ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 CONSOLIDATED FIRE ALARM COMPANY, OF NEW YORK, N. Y., A CORPORATIQNOF NEW YGBK.

Speccation of Letters Patent.

Patented Ang. i). 19M).

Application led April 32), 1903. Serial No. 154.957.

To all whom it may concern:

Be it vknown that I, Hunan iV. DEAN, a citizen of the `United States of America, and resident of Chicago, county of Cook, and State of Illinois, have invented a certain new and useful Improvement. in Combined T elephone and Alarm or Kindred Service Sys tems, of which the following is a specification. A

My invention relates to the application of alarm signal 4and kindred service to telephone exchange systems whereby the telephone circuits radiating from the central oice of the exchange and a portion of the telephone aoparatus at the exchange may be utilized for an additional purpose and an additional source of revenue.

As is well known the ordinary tele bone line of an exchange is idle and use ess a great part of the day and practically all of the night. A large roportion of the capital invested in a telep one. plant is, therefore, idle and' incapable of earning any revenue.

i f but by combining an alarm or other auxila5 iary service'with the telephone service by which the existing telephone apparatus is utilized without interruption or inconvenience to the telephone service, an additional earning capacity is imparted` to the capital thus invested in the plant.and this with onlya slight extra investment for the comparatively inexpensive extra apparatus required at each end of the telephone lilies. From the alarm Service point of vien', such a system is ideal for the reason that independent metallic circuits are used between the alarm transmittiers and the alarm receivers, whereas on account of the expense in thc ordinary alarm system, each circuit includes; many differentstations ail in series. The independent cirenit system permits the employment of simplified apparatus at each end while the series circuit system requires more or less complicated instruments to prevent interference of signals, and for various other reasons.

One of the main objects of my invention is to rovide-a combined telephone and alarm or indred service system that is practically and commercially operative: that to a large extent employl the circuits andapparatus of the telephone exchange. and one that dof-s not interfere with the exchange for iele- Phonic purposes.

The invention includes the provision of individual registers for thc lines whereby trouble on any ot' thc lines segregated and dors not aticct'the normal working ot the remainder of the iipes and registers. The apparatus is preferably operated from the central common source of current. used in connection with the telephone exchange whereby an extra expense for operating the alarm System is avoided. The alarm transmitter is arranged to permit reversal of the line wires in installing or repairing' the lines without. affecting the operation of the alarm system.

Another feature of the invention resides in the provision of visual alarm Signals in connection with the alarm .service iincs, whereby in the case of trouble on the lines the attention of the attendant is direeted to the particular line or iines.

The invention consists, further, in the provision of a mechanical lock for the alarm receiving devices at the exchange whereby current over the metallic line or over a partienlar side of the lineprevents the operation tions A and D to thc central ottico C of the exchange. At thc substatious any usual or desired telephone outtit may be employed,-

but px'et'erablj.7 such as is adapted fornse in connection with a common central source. of current. The apparatus shown comprises a transmitter 4 and a receiver 5 in a bridge of the line conductors whose normal distcon` tinuity maintained b v tluswitch hook G, while an ordinary polarized call bell 7 and a condenser S are connected in a permanent bridge of the telephone lie.

At thc central otiiee the line is represented :is usual by an answering jack J and a plurality of multiple jacks J2 and J3, each havwhich is grounded b 12 and 13 with the, live pole of the central 1nd common battery B, the opposite pole 0f conductor 14, The relay R2 controls the' ocal circuit of the line signal S which is preferably a small 1ncandescent, lamp.

The operators are provided with any sultable number of cord circuits, only one being represented in the diagram, each ofwhich 1s provided with an answering plug P and a calling plu;r l2 provided with Contact sur- -aces p, p fand p adapted to register with the corresponding contact surfaces ofthe spring jacks when inserted therein., The tip contact p'of theanswering plug P is connected by flexible strand t with the winding 'w of a suitable repeating coil while the corresponding contact of plug P2 is joined by a similar strand t2 with the repeating coil winding ,2v2 whichl is placed in inductive relation with said winding,r 'wg and both of which are connected at their inner ends with tbe'gronnfled pole of the battery B. A similar strand 8 joins the sleeveeontact p2 ofpluu P with lthe. winding 'w3 of the repeating coil which includes the winding' of the supervxsrv relay r, while the sleeve 'strand of plug P is connected by strand a2 with the windinry w of 'said repeatingI coil., placed in inductive. relation with the winding w, said lrtter strand likewise including the coil of supervisory relay r2. The inner ends of said viudin's 'm3 and w' are united to the. live' nole rf battery B. The ring' Contact 7f3 of conductor 15 through a suitable supervisory signal S2, usually u' the form of a small incandescent lamp, with the conductor 13 leading.' to the live pole of the battery B; while a similar third conductor 17 joins the con tact p of the plug l): through the supervisory signal 5" with the said conductor 13.

' The relays 1' and r' control respectively the sluints of the supervisory signals S2 and S3.

The operator-s head receiver lt), the Sec- I ondary winding of her induction coil 20, and a suitable condenser 2l, are adapted to be. connected a ross the answering end of the cord circuit oy means of any suitable listening key swit.: 1, her transmitter 22 in circuit with the primary of hcrinduction coil being charged from any suitable source of current, and which may be battery B. A ringing generator 23 adapted to nating or pulsating current is arranged to be connected with 'the calling end of the cord circuit by the depression of springs 24, Q4 of any suitable ranging key, the strands t2 -and a2 being at this time open to prevent the roduce alterh fact that the telephone system upon which the 'alarm or kindred service svstem is eagrafted continues to be operated in the same' manner in which itl has heretofore been operated in the absence of the alarm system. In order to adapt such lines for alarm sigmaling, the subscribers stations or other out-- lying stations are provided with suitable alarm signal transmitting devices connected with the telephone lines and by, means of which a signal, preferably distinctive. may

be sent to the central otlice. At the central ottice auxiliary alarm signal responsive de- `v1ces are provided to receive and* record the said alarm-signal so that the same may be attended to in the proper manner. This additional apparatus should be arranged so as to not normally interfere with the u'se of the systems for telephonie purposes.

represents the 'alarm signal transmitter at. the substation and comprises suitable springs 25 and 25 connected respectivelyf with the 'line conductors 2 and 3, and arranged to be'normally isolated, but when the pin wheel 27 is rotated to be thereby intermittently connected together' and thence to ground through the brush The alarm signal receiving` device F preferably at the central otiice comprises a magnet 16 haring diti'erential windings 29 and 30 interposed respectively in line conducthe lucl l is connected b means of a third l tors '2 and 3, Sothat current flowing in the metallic line does n'ot .operate the magnet. These coils are wound side by side, as shown. or superimposed in such' close relationship that the magnetic effects of the rapidly varying voice currents are neutralized and the voice currents are unimpeded. ll'heu, however, current traverses one winding only. or both windings in parallel, the core is magnetized and the armature is attracted. The armature vof tbe magnet is mounted upon the normally retracted spring.r

or lever 211, provided with a printing` point 32 adapted to impress the tape or ribbon 33, wound upon a spool 34, and which may be automatically set in operation by the operation of the magnet 1G.' This device registers the signal received from the substation, and in order that an audible alarm may be given to attract the attention of the attendant, the said movable part 31 1s arranged to close contact 35 in the circuit of the bell or other alarm 36 and battery 37. -This battery may be the same as battery B, and both battery and the alarm are preferably common to the exchange or to a large number ofzlines as indicated bythe dotted lines branching fron' the points 38 and 39. Each alarm signal receiver may have a visual signal associated therewith as indi- :cated by the target 36.

It is apparent that the use of the tele- I phone line for telephonie purposes does not' erates and causes lamp S to light. In

set in operation the nlarmsi al receiving devices. For example, subscriber A in calling for a connection takes up his receiver and completes a path for current over the metallic line from the battery B over conductors 13 and 12, through line relay R, contact 11 of relay R, the sleeve conductor 3 of the telephone line including Winding 30 of relay 16 to the substation 'and' thence back to the central oice over line conductor 2 through winding 22 of relay 16 and to ground through spring -10 of cut-off relay. R. This current flowing through the differential windings of the magnet 16 in series does not operatg it and the alarm signal receiver remains irresponsive.d But relay R2 opresponse to the call the'operaor inserts the plug P of her cord circuit in the jack J and connects her instrument with the cord circuit by means of the listening key. The in- -sertion of the plug P closes a path' for cur rent from battery B, over the third conductors 13 and 15 through contacts' p3 and j and thence by way of conductor 9 to the cut-0H relay R, which operates to sever the line conductors 2 andv 3 at springs 10 and 11 thereof.' Owing to the fact that the re ceiver at the substation A is now removed from its hook, current from battery B will circulate over the two strands of the cord circuit and inthe metallic telephone line in the same manner'as before, thus again not affecting the magnet 16 of the receiver.' The supervisory relay r is also actuated to rlose the shunt of the supervisory lamp'Sz which is thus rendered inert. Upon learning the number of the party Wanted the line is tested in the'usuaf'iway to determine its idle or bus)y condition. If idle the test* rings j of the jacks -are connected through the -winding of the associated cut-oli' relay to ground, and since the tip of the calling plug V P2 is likewise grounded by branch 14 no I a third cuit at 55 board with the live pole of the battery B so ilow of current results over said bauch, and no click is received in the operator`s receiver. If the line isl'husy on the other hand` the test rings of the jacks are connected through conductor 15 or 17 of the cord cirthe other 4section of the multiple Y particular register operating.

that when the tip contact of the testing plug is brought into contact with the test. ring. a flow of current takes place through the winding 102 ofthe repeating coil which in- -ductively causes a click in the opcrator's recciver. y

Assuming that the line wanted is found idle the calling plug P2 is inserted in one of the multiple jacks of theline and the ringing generator operated. This generator `sends current over the metallic line in a manner similar to the battery B though of different character to operate call bell 7 at the substation. Here again owing to the differential coils of magnet 16 inthe called line the alarm register of the line is not actuated. After the subscriber has been callcdand before his response the supervisory lamp S3 is lighted over the said third conductors and is extinguished only when the subscriber responds by the operation of supervisory relay 1'5. During conversation the battery B is furnishingcurrentover tently closes the springs 25 and 26 totgether -and to ground. The grounding o doctor 3 permits current. from battery and 12, through thecon- B to ow over conductors 13 line relay Re, thence over the sleeve conductor 3 of the line, winding 30 of magnet 1 6, thence to spring 25, wheel 27 and brush 28 to ground. This current in winding 30 energizes the magnet 16 which attracts its armature and accordingly registers the alarm signal by means of the pencil or point 32 upon the tape 33 which is now being unreeled from spool 34 by the register mechan- .ismz At the' same time the contact 35 is 'closed and alarm 36 is operated thus calling the attention of the attendant. Likewise the visual indicator 36* is exposed and serves to direct the attention of the attendant to the It is. of courses unnecessary for the above mentioned operation to ground the line conductor 2, but it is convenient in view of the fact that it does no harm and the linernen in iustallinvr the system and connecting the 'subscribers lineto the central oice as well as in making repairs are liable to reverse connect-ions of the two line conductors. When, however, provision is made -for grounding both conductors by the alarm signal transmitter, such reversal of the line connections in no way affects the operation of the alarm apparatus. The lirie relay R2 may respond to this current and the line signal S may be soV fiasiiedbut the operators at the exchange terposed at the main distributing board iniiould be instructed-to disregard such viuterniittet lighting or flashing of the lamps,

so that the usual Working of the exchange would not be interfered with. Should the alarm signal transmitter he set in operation during the time that the cord circuit is connected with the line, current will flow in the sanie'maniier over the sleeve conductor of the telephone line but through the sleeve strand of the connected cord circuit but will not dow over the tip side of the line since itj is grounded at the transmitter E. This might interfere with' any conversation oing l A transmitter should such type-of service be desired, as by carrying the connection of spring 26 to line conductor through normal contacts of the hookswitch, or in any .other desired manner.

I have indicated the alarm signal transby the opening of the local alarm-circuit through the meltiii of a fuse-18 or by the key switch 18" whic i deiiergizes magnet 18* and releases the wheel 27 and its driving mechanism. It will he understood that the transmitter may he varied to meet the de. inauds of any type of alarm and kindred service desired without departing from the spirit of my invention. The construction and operation of such transmitters 'is well ,I

understood in the art ai. tion thereof is deemed unnecessary.

Asahovc pointed out, the registers F are further descrip- 3 individual to each line, which is of particular advantage in case of trouble on any of the lines as ior example the common trouble of an accidental ground oii thc liiic outside the central o iice. This would be made manifest in thc present arrangement by the continued display of visual signal 3G* and the sounding of pilot signal 36S and only the f one register would lic put out of service; but iii the i-.asc oi the cimiiiioii register artliroii'iiout by the accident on one line.

.Still other advantages exist; the. record for each line may lic conveniently preserved as i with the individual register is of coiivciif iciicc in locating thc register tlms hold iii upcii the linciuid sei-.ves further by drop- -piiig back to automatically indicare when the trouble has heen remedied.v

The receiver magnets are preferably in- 'at the central oiiice. T e latter includes l.

magnet 50 placed in the line conductor 3 of the telephone line and shuntcd by a nonindiictive resistance 51 and serving to actuate the pencil or point 32 as before described. and also to close the circuit of coincluded in the line conductor 2 and shunted by non-inductive resistance This magnet hss an armature 54 carrying a catch 55 adapted when the armature is actuated to hook over the end of armature 31 and prevent its operation. Vf'hen current traverses linecoiu'luctor 3 in response to the operation of the alarm transmit-ter E, thc magnet 50 is operatcd and the signal is received and registered in the usual manner. But when current flows over both line conduct-ors in series the magnet 52 is also energized and since its armature is adjusted to respond before ariiiziture 3l of magnet 50 is drawn up, the catch hooks over and locks the Dart 31 i'oii'iopcratiiig. Thus ivliile current is Sowiiig over llic metallic liiic :is during the Sending of a call iroiii the suhscribers station to g the ccnii'zil oflicu for a connection, or in calling :i subscriber from thc central oiiice; or

during conversation. die said register is locked and prevented from operating. The alarm transmitter is the saine as that Shown iii Fig. 1 The lino circuits iii this gure diil'er soiiiciihat from those shown in Fig. 1, and principally in that thc switchboard sections of tlic lines and the cord circuits require mil)Y tuo conductors. The line c011- doctor is normally grounded at one spring 3 of thc cuboii' relay ll". .vliilc the conductor 3 rangement thc whole service would bei is iioriiiiilli' connected through :i sprin of said relay with flic liuc. relay R, wliic is i thence comici-lcd will thc common battery liz. 'l`lic winding of said rut-oil' relay Rs i is grounded from the sleeve conductor of the I of tlic liuc. 5 centi-:il olliz-o f or a connection. current Hows over the metallic luie. locking the alarm sig iial rwciviog apparatus at the central oliice locked position as by an accidental ground lioriiizilly disconnected switch hoard section Wln-n flic subscriber calls the :iiid actuating thc liiic rela-i.' l2. In respouse tothe signal the pliigvPo the cord circuit is inserted iii one of the iacks. thereby periiiittlng current lo flow from the liuticry B2 through supervisory relay-1", the

me, l

sleeve conductor .i of the. cord, and thence over sleeve conduetorl of tlic switchboard section of the liuc. and through the cut-oli relay R3 to ground. This. connects conduc- 5 tors and 3 with the said switchboard sec tion and renders the line signal inoperative. Owing'to the fart that the subscribers receiver is in use current from the battery 1 2.

also circulates over the metallic line and o therebyv actuaires supervisory relay rs to open the circuit of supervisory signal to render the same inert. The register mechanism rtniains inoperative. A iter connecting her receiver with the cord circuit by means of any suitable listening lrev arl receiving the order she tests the condition of the wanted line by touching the tip of the calling plug P2 to one,-of the testrings in the usual Way and determines Iits .idle or busy condition. 2g The insertion ofr tbe plug I in the jaclt of the idle line serres to operate sleeve supervisory relay 1' and relay R3 of the line. The supervisortv signal S3 is new actuated owing to the fact'tliat relay T5 is not yet operated. 'Depressing the springsl of the ringing key connects the generator Sil with the tip strand of the cord circuit and operates the subseribers bell, a return mth for the ringing current being provided in the usual inanner through the alternate contact of the sleeve spring 24 of said ringing key. The cut-olil relaj,y RJ is maintained actuated during ringing by current from the common source B3. The response o the called subscril'ier energias-s magnet w" to cut out lmnp S3.

During coiiversaitioii the voice currents are not affected by the magnet.` 5C' and- 52 since they a/re shouted by the non-inductive resistances 51 and 53. The batteries B2 and Bs f ish currentoutv lover'tlie respective lines to charge the transmitters, the registers KAFf bein thereby locked. Grounding both -line con uctors as in former instance guards against errors in connecting the external line circuits with the central otlice. The mag- .nets and 52 of the registers may be interposed in thel lines by iiicans ofextra ler-- minals 43 on tlie distributing frame indi-- 50 cated by terminals ill. and 42. lie registers are preferably individual as in Fig. l, but

Athe mechanical lockingl of the armature of the magnet 50 is, ofcourse independent of this feature since the marker 32 and tape 33 could be dispensed with and an ordinary register substituted for the bell 36.

Other modifications may obviously be made in the details of my invention Without de arting from its scope or principle. aving described my invention what I claim is:

1. In a common battery telephone exchanve, the combination with a plurality of e eplione' lines leading from subscribers stations to the central station, of telephonie apparatus including a common source ofY current a/t'the Suid central station to cooperate with said lines for conversational purposes, telephone sets at the substations adapted for use with said central source of current, alarm transmitting" apparatus at outlying points adapted to cause the tloiv of distinctive signaling currents-over the lines from said central source of current, and alarm receiving and registering apparatus at the central station individual to cach line, said individual receiving and registering apparatus having an electro-magnet in each side of the line, means for operating said receiving and registering appaai, rat-us when one of said magnets is energized and to prevent the operation of the same when the other magnet is energized whereby said receiving apparatus is responsive to the said distinctive signaling currents and 35 irresponsive to the telephone signaling and talking currents, substantially as described.

2. In a telephone exchange, the combination with a lurality of telephone lines leadino'. from su scribers stations to the central 90 oflice, of telephone sets at the substations and telephonie apparatus at the said central station to cooperate with. said lines for conversational purposes, alarm transmitting apparatus at outlying points adaptedto transmit distinctive signaling currents over the lines, an alarm receiving apparatus in the .lineat the central station responsive to said distinctive signaling currents, and a mey clianical lock for said 'receiving apparatus 100 adapted when 'the telephone signaling or talking currents are present on the line to lock said receiving apparatus and revent its operation, substantially as descri d.

3. In a telephone exchange, the 'combina- 105 l tion witha plurality of telephone lines leading from the subscribers stations tothe oentral station, of telephone sets at the sub-, lstations and telephonie apparatus at the said central stationzto cooperate with. said lines for conversational purposes, alarm transmitting apparatus at outlying points adapted to transmit distinctive signaling currents over the lines, alarm receiving' and registering apparatus at the central'statiog -lll individual to each line and responsive to said distinctive signaling currents, said receiving and'registering apparatus having an electromeclianism in the telephone line, and

a mechanical lock for said receiving appa.-

ratus'controlled by said electrofmechanism and adapted whenthe telephonesi ling or talking currents are present on t e line to lock said receiving and registering apparatus and prevent its operation, substantially as described. 4. n a common battery telephone ex-I change, the combination with a plurality of telephone lines leading -:from the. subscribers stations to the central station, of 33" CII ' controlled `by` said magnet windings and adapted ivlieii the telephone signaling or talking currents :ii present -on the line to lock said receiving apparatus and prevent it from operation, substantially as described.

5. ln a common battery telephone exchange, the combination with a plurality of telephone lines leading from the subscribers stations to the central station, of telephonie apparatus at the central station including a common source of current to cooperate with said lines for conversational purposes, telephone seats at the siilistations adapted to c0- operate with said coiiinioii source of current, alarm transmitting apparatus at outlying points adapted tio transmit distinctive signaling currents over thc telephone lines from said central source, alarm receiving and registering apparatus uttlie central station iiidividual to cach line and responsive to said distinctive signaling currents, said receiving and registering apparatus having a magnet vwinding in each sido of the line, and a Lnechanical 'lock controlled Aby said magnet windings and actuated when telephone signaling or talking currents are present on the line to prevent said receiving and registering apparatus from operation, substantially' is described.

(l. ln a telephone exchange, 'the combination with a plurality,l of telephone lines leading from the subscribers stations to the central station, of telephone sets at tlir stilistations and tclephoiii. apparatus uttlic central station to copcl'ate with said lincs for conversational purposes, an alarm transmitting 'apparatus iit an outlying point adapted to send distinctive signaling currents over one side of a line only, alarm receiving 'apparatus at the, central station having a magnet in euch side of the line, :i mechanical lock for said receiving apparatus, oneof said magnets serving to operate the receiving mechanism of said apparatus and the other to operate said lock.

60 .whereby when the sai'l alarm transmitter is operated, said receiving mechanism is actuated. and when current is ,present on the other sii? I l l fue line said lock is operated to pra-x actuation ofsaid receiviiig apj substantially as descrlbed.

' rent at thc central stal.

7. In common battery telephone exchange system mi combination with a telcphoneline 'leading from the subscriliers station to the central station, of tcleplio'iiic apparatus at, the ntralstation including a common source of current to cooperate with said lino for conversational purposes, of a telephone set at the substation adapted for use in connection with said common source, an alarm transmitting apparatus .at an outlying point adapted to transmit clistinctive signaling currents over one side of the telephone circuit from said source, alarm receiving and registering apparatus at thc central station, said apparatus having a magnet in each .side of the line and thc regl-tel being individual to the line, one 'of said magnets serving to actuatc -thc receiving and registering mechanism and the other to prevent its operation, whereby said receiving and registeringa apparatus is responsive to said distinctive signaling currents and is locked and prevented from operation r when' telephone signaling and talking currents arc present on tlic line, sub-A stantially as described.

8. Inv a common battery telephone exchange, the combination with a telephone line leading from thc subscribers station to the central station, of telephonie apparatus at. the said central station including'a coinmon source of current to copernte' with said line for conversaifional purposes, a telephone set at the substation adapted for use 1n connection with said common source, an alarm transmitting apparatus at .an outlying point adapted to transmit distinctive`signaling currents over one side only ot the telephone circuit alarm receiving at the central station, said ap 'aratus having a magnet in each .side o f the ine, a mechanical lock for said receiving apparatus, one of said magnets servingy to actuate thel receiving and registering-inechanism and the other to operate said lock, whereby said receiving andv registering apparatus is responsive to said distinctive signaling current, over one side of the-liuc and is ticked and prevented from operation when telephone signaling and talking currents are present ori the lime, substantially r1 uescribed.

U. In a common battery telephone system, the combination with a plurality oftclephone lines leading from subscribers sta.- tions to a central station, of telephonie apriaratus incliulirg;A a common source or curi ion to cooperate v, ith said lines for conversational pur oscs, telephone Seis at the siilistafmns aiapted for use with said central source of current, alarm transmitting apparatus at outlying points adapted to cause the flow of distinctive signaling currcnts over the line from from said coinmon source, an'l registering apparatus said common source of current, and alarm 'receiving and registering apparatus individual to each line and having mechanism in each side of the line co-acting in response to the .said distinctive signaling currents hut 'in obstructive opposition for tele hone sig- .nling or talking currents, sai

` common source of curi-cnt. having one terminal nor- 'mally grounded and having its other terminal normally connected with one side-of each line, said line hein" grounded at Ithe signal transmitting mccianism when the Y signal is being transmitted, substantially as described.

10. In a common battery telephone exchange, the combination with a plurality of telephone lines leading from subscribers' sta-.

, tions to the central station, of telephonie apparatus including a common source of cur-l rent :it the said central station to coperate with said lines for conversational purposes,

` telephone sets at the substation adapted for usc with said central source of current, alarm transmitting apparatus at outlying 'points adapted to cause the How of distinctive signaling curi-ents over the lines from said central source of ciiri-ent, and alarm receiving and registering apparatus at the central station individual to each line, said individual receiving and registering apparatus having electromagnetic-inechanism in each side of the line co-acting in response to the i said distinctive signaling currents but in obstructive opposition for the telephone signaling or talking currents, said common source of current having one terminal normally grounded and having its other terminal normally connected with one wire of each line, said wire being grounded at the signal transmitting mechanism when the signal is being transmitted, substantially as described.

11. In a common battery telephone sys-- tem, the combination with a plurality of telephone lines leading from subscribers sta- Y tionso a central station, of telephonie apparatus including a common source of cur rent at the centi-al station to coperate with said lines for'conveisational purposes, telephone sets at the substations adapted for use vwith said central source of current, alarm transmitting apparatus adapted to cause the ow of distinctive signaling currents over lthe line from said common source of current,

and alarm receiving and registering apparatus individual to each line and having electromagnetic mechanism in each side of the line co-acting iii response to said distinctive signaling currents, said common source of. current having one terminal nor- 1 mally grounded and having its other terminal normally connected to one side of each f line, said lines being grounded at the signal v Y transmitting mechanism when signals are beingtransinitted, substantially as described.

12. Inh a cominonbatter'y telehone exclianve, the combination Witha p urality of telephone lines leading' from subscribers stations to the central station, of telephonie apparatus including a common source of current at the central statron to coperatie with said lines for conversational purposes,

telephone sets at the substations adapted for use with said telephonie a paratus and common source of current, a arm transmitting apparatus at outlying points adapted to cause the dow of distinctive signaling currents over the lines from said central sourc'e, and visual signaling and registering apparatus at the exchange individual to each line,

said individual signaling and registeringapparatus having 'electromagnetic mechanism in each side of the line co-acting in response.

t0 said distinctive signaling currents but ln obstructive opposition for the telephone-sig naling and talkin currents, said common, source 0f current aving one terminal noimally grounded and ,having its otherl ter?. miiial normally connected with one side of each line, the line being grounded 'on that ,side at the signal transmitting mechanism when the signal .is being transmitted, substantially as described.

13. In a common battery change, the combination withl p urality of telephone' lines .leading lfrom subscribers station to the central station, of telephone apparatus includin current, at thc sai central station to co operate with said lines 'for conversational purposes, telephone sets at the substations adapted for use with said telephone appa#v tele hone exa` common source of ratus and central source, alarm transmiting and talking currents, said common,

source of current having one terminal normally grounded and having its ot r ter' minal normally connected with one side of each line. the line being grounded on that side at the signal transmitting mechanism when the signal is being transmitted, subvstantially as described.

14. In a, common battery telcphon e'-ex-A change, the combination with a plurality of tele hone llines leading from subscribers" stations to a central station, of telephonie apparatus including a common source of current at said central statioirto coperate with `aid lines for convrational'purposes, 'iilfphono sots at the snbsmtions adapted -l'or use with said. line appuratns and said other Side of the line. whereby it does not" respond tcthe telephone' signaling and-tallo' 15 ing currents, said common Sourire of cin-rent having one terminal normally grounded and its other terminal normally connected to the signal transmitting side of euch line.

,Signed by me at Chicago, county of Cook, 2o State of Illinois, hthis 27th dav of April,

WILLIAM W. DEAN. Witnesses:

Romain* LEWIS AMES, E. A. GABLocx. 

